Leather drying



, .March 9, 1937. w BACKUS 2,073,592

LEATHER DRYING Filed NOV. 26, 1935 INVENTOR: 7mm, T Backus,

Patented Mar. 9, 1937 LEATHER DRYING Wallace '1'. Backus, Philadelphia,Pa., assignorto J. Edwards & 00., Philadelphia, Pa., a corporation ofPennsylvania Application November 26, 1935, Serial No. 51,576

2 Claims.

My invention relates generally to drying methods and apparatus andparticularly to leather drying methods and apparatus. In the past,leather drying. has been done -both by exposure 5 to the atmosphere andby machine methods to speed up the process. The dimculty with the formermethod is its slowness and lack of control. Frequently atmosphericconditions are not conducive to drying and expensive delays from thiscause are normal occurrences. The machine methods which attempt to speedup the drying process have the common disadvantage of impairing thestructure of the leather and consequent- 1y producing an inferior gradeof leather. Many involved methods and machines have been proposed toovercome the dangers of rapid drying of leather and particularly shoesand yet the problemremains of accomplishing the objective by a simpleand practical means. How can shoes be dried-at different stages of theirmanufacture with rapidity and independent of the atmospheric conditionswithout impairing the structure of the leather or of the partiallyconstructed shoe? My invention solves this problem by a departure fromthe usual type of drying methods and machines which use heated air andrapidly moving air currents. These two properties of the drying mediumare lacking in my invention and it is their absence which to aconsiderable extent the detrimental effect of heat and strong currentsof rapidly moving drying medium and abstract moisture from the leatherwithout distorting its structure, either surface or internal.

Consequently one of the objects of my invention is the provision, of asimple method and machine which will rapidly dry leather or othersubstances independently of atmospheric conditions and without injuringthe structure of the leather or the workpiece. Another object of myinvention is the provision of such amethod and machine which may takeadvantage of satisfactory atmospheric conditions by using the atmosphereas a drying medium at such times. Another object is'the provision of ameans of leather drying which is permanently open to the workmen withoutsubjecting them to the discomfort of heated blasts of air. Other objectsand advantages of my invention will become apparent from the detaileddescription of a preferred embodiment thereof which follows and whichhas reference tothe. accompanying drawing which shows a side view of myinvention partially in section. 55 My invention comprises generally, aswill appear in the drawing, drying units I, a d'ehucharacterizes mymethod. and machine. I avoid midifying unit 2 and conduit 3 and abooster fan 4. The drying'unit l comprises a sturdy frame 5, sprocketwheels 6 mounted at the ends of shafts 8, a movable rack 1 running onthe sprocket wheels 6, a motor ll secured to the frame and 5 connectedto one of the sprocket wheels 6 by reduction gears l2 and. I3, and ahood l4 covering the upper portion of the frame 5 and rack I. Themovable rack I operates on the sprocket wheels 6 after the manner of thewell known endless chain. 1 Each rack board I5 is pivotally suspendedbetween the rack chains l6 so that the weight of the board i5 and shoesl'l keep the boards l5 from turning over as the chains l6 travel abouttheir sprockets 6. The shoes I! fit in openings in the rack boards andno other fastening is required. of course, many other forms of racks andwork holders are well known in the art and they could be substitutedhere. For this reason the structural details of the drying unit I havebeen omitted as irrelevant to the invention, and conventionalindications adopted. The motor I l moves the rack i very slowly throughthe reduction gears l2 and I3.

The 'dehumidifying unit 2 may be one of the several types now wellunderstood in the art and obtainable on the general market. It must,however, be of the type which dehumidifies the air without substantialheating ofthe air which leaves the dehumidifying unit. An incidentalrise of temperature amounting to 10 or 20 above the atmospherictemperature would not be detrimental to the operation of my invention,but any substantial heating of the air would partially if not whollydefeat the purposes of my invention. I wish, therefore, to distinguishbetween incidental- 1y heated air or drying medium and air or heatingmedium which has been purposely subjected to a definite heating process.In the former there are comparatively small changes of temperaturewithin about 20; in the latter there is a relatively large increase oftemperature.

The hood I4 is secured to the upper portion of the frame 5 and leaves asubstantial portion of the rack I exposed for access by workmen whoplace the shoes I! during the motion of the rack I. Because the hood Iexposes a substantial part of the rack I, a working station can bepositioned adjacent the rack I eliminating an intervening work transferbelt which would be necessary in the case of a hood closed at thebottom.

A closed hood would require a work transfer belt to carry work out ofthe drying unit to the workman. The top of the hood I4 is connected tothe conduit 3 through a butterfly valve .20 by means 5 of which the slowflow of the drying medium is controlled for each individual drying unitI.

The conduit 3 which connects the drying unit I to the dehumidifying unit2 is equipped with an atmospheric connection 2| through which theatmosphere may be admitted when suitable as a drying medium. Theconnection of the conduit 3 to the hood I4 is at such an angle andposition that the drying medium does not come into direct contact withthe shoes I! as it moves out of the conduit 3. A baflle could if desiredbe supplied to further deflect the incoming drying medium from directlyflowing on to the moving shoes IT. A butterfly valve 22 controls theatmospheric connection 2|. Another butterfly valve 23 controls the flowof drying medium from the dehumidifying unit 2. All the butterfly valves20, 22 and 23 have operating chains 24 accessible to the operator fromthe floor.

The booster fan 4 installed in the conduit 3 may be of any slow runningtype. Its purpose is to insure a slow and gradual diffusive movement ofthe drying medium through the conduit 3 and in the hood l4. It isimportant that this fan 4 keep the drying medium in a state of gradualprogress along its course Without developing any well defined or rapidair currents.

While the operation of my invention has been described to some extent inconnection with the above detailed description of the apparatus, thefollowing additional description of its operation will behelpful,particularly in fully understanding the method on which the aboveapparatus works. First the dehumidifying unit 2 is started and thedrying units I are filled with dehumidified air by opening the butterflyvalves and 23. The motor H is started and the rack 1 begins to moveslowly. A workman who has a work station at the bottom of the rack I nowplaces shoes I? I on the rack boards l5 as he receives these shoes I!from the preceding work station. It is to be noted here that this workstation at the bottom of the rack 1 would not be possible were it notfor the fact that the rack l is exposed which would be impossible in thecase of a heated drying medium. The drying medium gradually moves inthrough the top of the hood I4 well above the shoes l'l moving on therack 'l at the top of the hood I4. This avoids a direct movement of airon to the shoes I! and causes a gentle diffusion of the drier air fromthe top of the hood l4 toward In case the unconditioned atmosphere issuiflciently dry to serve as a drying medium, it can be admittedthroughthe atmospheric connection 2| as long as the dry atmospheric conditioncontinues. It is thus seen that my invention results in a rapid dryingof the shoes I! without the deleterious effects that frequently resultfrom the use of heated air in blasts or rapid currents. Instead ofcontrolling the blasts and the amount of heat as has been admitted inthe. prior art, my invention avoids them. The apparatus is simple inconstruction, positive in its operation and efficient in its results. Iteliminates a number of steps that have been resorted to in the prior artto avoid the deleterious effects on leather when the drying isartifieally speeded up and accomplishes an economy with better results.

While my invention has been described in some detail with reference to aspecific embodiment, various changes in the form of the apparatus usedand of the steps of the method employed are within the contemplation ofthe invention and such changes should not be admitted to constitute adeparture from the spirit of the invention as hereinafter claimed.

Having thus described my invention, I claim:

1. A shoe drying apparatus comprising a vertical movable rack in whichthe horizontal movement is relatively small in comparison to thevertical movement, a dehumidifying unit producing a drying medium atsubstantially atmospheric temperature, an open bottomed hood attached tosaid dehumidifying unit by a conduit iii having a substantiallyhorizontal discharge into the top portion of the hood, said hood beingsuspended over the upper portion of said rack to form the dischargeddrying medium into a slowly changing body merging with the atmosphere atits open end, and a means for slowly introducing the dehumidified mediumby a gradual diffusion from the top of said hood.

2. A shoe drying apparatus comprising adehumidifying unit producing adrying medium at substantially. atmospheric temperature,- a dischargeconduit leading from said unit, an open bottomed hood connected to thedischarge end of said conduit, said conduit being positioned atsubstantially the top of said hood and directed to discharge the dryingmedium substantially hori-. zontally, and a vertical rack having itsupper portion under said hood for moving the shoes up and down throughsaid hood, said rack being of such proportions that thehorizontal'movement of the shoes in the hood is relatively small incomparison to the vertical movement.

WALLACE T. BACKUS.

